Granular composite additive for polyolefin, process for producing the same, and polyolefin composition containing the same

ABSTRACT

The present invention provides a multi-component granular additive for polyolefins which has a strength and a function which enable the additive to be dust-free and be of components-in-granule type. It comprises 10 parts by mass of a nucleating agent comprising an alkali metal salt or hydroxyaluminum salt of an aromatic monocarboxlylic acid or comprising an alkali metal salt or hydroxyaluminum salt of an acid aromatic phosphoric ester compound, 1 to 50 parts by mass of a phenolic antioxidant, 5 to 50 parts by mass of polyproylene, and 0 to 500 parts by mass of one or more optional additive components other than the nucleating agent and the phenolic antioxidant.

This application is the U.S. national phase of international applicationPCT/JP01/09596 filed Nov. 1, 2001 which designated the U.S.

TECHNICAL FIELD

The present invention relates to a multi-component granular additive forpolyolefin, the additive containing a specific nucleating agent, aphenolic antioxidant, and polypropylene as essential components, and toa method for producing the additive. The invention also relates to apolyolefin composition containing the additive.

BACKGROUND ART

A variety of additives are incorporated into polyolefins, such as astabilizer for imparting process stability against heat, oxidation, etc.during molding thereof and storage stability of the resultant moldedproducts against light, heat, oxidation, etc.; a modifier for impartingstrength, transparency, color, etc. to the molded products; and acatalyst deactivator.

Generally, these additives are used in powder form to polyolefins duringmolding thereof. However, use of these powdery additives producesairborne dust, which is problematic in terms of operational safety. Inaddition, a number of additives which differ in terms of specific weightand form must be uniformly mixed in arbitrary proportions, therebyraising problems in weighing and operation.

According to one proposed approach to solve these problems, a number ofpowdery additives are mixed in arbitrary proportions in advance, and theresultant mixture is shaped into granules. Through granulation,generation of airborne dust can be suppressed, and cumbersome work forformulating and uniformly mixing the additives can be mitigated, tothereby realize so-called dust-free, components-in-granule additives.

Recently, studies are focused on a granulation system employing adry-compacting apparatus and a pellet mill, and a granulation methodmaking use of a binder such as wax, paraffin, or steramide. However, theabove granulation system is unsatisfactory, in that granules produced bymeans of the system have poor mechanical strength and are readilycrushed to fine grains, thereby generating airborne dust, and thatuniform mixing cannot be fully attained. In addition, use of a binderresults in migration of unwanted compounds into polyolefin.

Japanese Patent Application Laid-Open (kokai) Nos. 5-179056, 6-91152,and 8-333477 disclose mixed granular additives and methods for producingthe additives. Although these additives are almost satisfactory in termsof physical properties, functions thereof require improvements. Thus,there still remain problems in relation to integration of additives intogranular form.

To crystalline polyolefins; e.g., α-polyolefins such as low-densitypolyethylene, linear-low-density polyethylene, high-densitypolyethylene, polypropylene, poly-1-butene, poly-3-methyl-1-butene, andethylene/propylene block or random copolymers, an antioxidant is addedin order to inhibit oxidation during molding and to prevent coloring anddeterioration of physical properties. A nucleating agent must also beadded to crystalline polyolefins in order to overcome drawbacks thereof;e.g., a slow crystallization rate after heat molding, progress ofcrystallization after molding, poor strength, and poor transparency. Thenucleating agent must be dispersed uniformly in polyolefin resin so asto maximize the effect thereof. However, another problem is that, whenthe nucleating agent is granulated through the above-mentioned method,the resultant granules have impaired dispersibility, failing to fullyattain the effect thereof.

In view of the foregoing, an object of the present invention is toprovide a multi-component granular additive for polyolefin, the additivehaving a strength and functions suitable for serving as a dust-free,components-in-granule additive. Another object is to provide acomposition containing polyolefin resin and the additive.

DISCLOSURE OF THE INVENTION

The present inventors have carried out extensive studies in order tosolve the aforementioned problems, and have found that theaforementioned problems are effectively solved by a multi-componentgranular additive for polyolefin, the additive having specificcompositional proportions. The present invention has been accomplishedon the basis of this finding.

Accordingly, a first invention provides a multi-component granularadditive for polyolefin, the additive comprising a nucleating agent thatcomprises an alkali metal salt or hydroxyaluminum salt of an aromaticmonocarboxylic acid or comprises an alkali metal salt or hydroxyaluminumsalt of an acid aromatic phosphoric ester compound, in an amount of 10parts by mass; a phenolic antioxidant in an amount of 1-50 parts bymass; polypropylene in an amount of 5-50 parts by mass; and at least oneadditive component, serving as an optional component, other than thenucleating agent and the phenolic antioxidant in an amount of 0-500parts by mass.

A second invention is drawn to a specific embodiment of amulti-component granular additive for polyolefin according to the firstinvention, wherein the nucleating agent is a compound represented byformula (I):

wherein n represents 1 or 2; when n is 1, M represents an alkali metalatom; and when n is 2, M represents hydroxyaluminum.

A third invention is drawn to a specific embodiment of a multi-componentgranular additive for polyolefin according to the first or secondinvention, wherein the phenolic antioxidant istetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methane.

A fourth invention is drawn to a specific embodiment of amulti-component granular additive for polyolefin according to any one ofthe first to third inventions, wherein said at least one additivecomponent contains a phosphorus-containing antioxidant.

A fifth invention is drawn to a specific embodiment of a multi-componentgranular additive for polyolefin according to any one of the first tofourth inventions, wherein said at least one additive component containsan alkali metal salt or alkaline earth metal salt of an aliphaticmonocarboxylic acid.

A sixth invention is drawn to a specific embodiment of a multi-componentgranular additive for polyolefin according to any one of the first tofifth inventions, wherein the granular additive has a ratio by mass(percent pulverization) of the particles which pass through a 16-meshsieve of 1.0% or less as measured in a pulverization acceleration testby use of a shaking apparatus.

A seventh invention provides a method for producing a multi-componentgranular additive for polyolefin as recited in any one of the first tosixth inventions, characterized by comprising granulating a raw materialcomprising constitutional components at 150° C. to 270° C.

The present invention further provides a composition comprisingpolyolefin resin and the multi-component granular additive forpolyolefin according to the first invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an electron microscope photograph of a broken face of TestSample A, with points (1) and (2) indicating the sites at whichcomposition analysis has been performed.

FIG. 2 is an electron microscope photograph of a broken face of TestSample B, with points (3) and (4) indicating the sites at whichcomposition analysis has been performed.

FIG. 3 is an electron microscope photograph of a broken face of TestSample a, with points (5) and (6) indicating the sites at whichcomposition analysis has been performed.

FIG. 4 is an electron microscope photograph of a broken face of TestSample b, with points (7) and (8) indicating the sites at whichcomposition analysis has been performed.

BEST MODES FOR CARRYING OUT THE INVENTION

Modes for carrying out the invention will next be described.

The nucleating agent of the present invention comprises an alkali metalsalt or hydroxyaluminum salt of an aromatic monocarboxylic acid orcomprises an alkali metal salt or hydroxyaluminum salt of an acidaromatic phosphoric ester compound (hereinafter may be referred tosimply as nucleating agent). Examples of preferred aromaticmonocarboxylic acid metal salts which can serve as the nucleating agentinclude the compounds represented by the following formula:

wherein R represents a C1-C8 alkyl group; m is an integer of 0 to 2; nrepresents 1 or 2; when n is 1, M represents an alkali metal atom; andwhen n is 2, M represents hydroxyaluminum.

Examples of the alkyl group represented by R in the above formulainclude methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl,isobutyl, amyl, isoamyl, tert-amyl, hexyl, cyclohexyl, heptyl,isoheptyl, tert-heptyl, n-octyl, isooctyl, tert-octyl, and 2-ethylhexyl.Examples of the alkali metal represented by M include lithium, sodium,and potassium.

Examples of the acid aromatic phosphoric ester compound metal saltswhich can serve as the above nucleating agent include compoundsrepresented by the following formulas:

wherein each of Rs represents a C1-C8 alkyl group; m is an integer of 0to 2; n represents 1 or 2; when n is 1, M represents an alkali metalatom; and when n is 2, M represents hydroxyaluminum.

Examples of Rs and Ms in the above formulas include those recited withrespect to the above aromatic monocarboxylic acid metal salts.

Among these nucleating agents, compounds represented by formula (I):

wherein n represents 1 or 2; when n is 1, M represents an alkali metalatom; and when n is 2, M represents hydroxyaluminum, are particularlypreferred, since these compounds impart excellent transparency andstrength to polyolefin.

Examples of the alkali metal represented by M in the above formula (I)include the above-recited elements.

The phenolic antioxidant of the present invention is a known antioxidanthaving a phenol skeleton in its molecule. Examples include2,6-di-tert-butyl-p-cresol, 2,6-diphenyl-4-octadecyloxyphenol, stearyl(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, distearyl(3,5-di-tert-butyl-4-hydroxybenzyl)phosphonate, tridecyl(3,5-di-tert-butyl-4-hydroxybenzyl)thioacetate,thiodiethylenebis[(3,5-di-tert-butyl-4-hydroxyphenyl)propionate],4,4′-thiobis(6-tert-butyl-m-cresol),2-octylthio-4,6-di(3,5-di-tert-butyl-4-hydroxyphenoxy)-s-triazine,2,2′-methylenebis(4-methyl-6-tert-butylphenol),bis[3,3-bis(4-hydroxy-3-tert-butylphenyl)butyric acid] glycol ester,4,4′-butylidenebis(2,6-di-tert-butylphenol),4,4′-butylidenebis(6-tert-butyl-3-methylphenol),2,2′-ethylidenebis(4,6-di-tert-butylphenol),1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane,bis[2-tert-butyl-4-methyl-6-(2-hydroxy-3-tert-butyl-5-methylbenzyl)phenyl]terephthalate,1,3,5-tris(2,6-dimethyl-3-hydroxy-4-tert-butylbenzyl)isocyanurate,1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate,1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzen,1,3,5-tris[(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxyethyl]isocyanurate,tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methane,which may also be calledtetrakis[methylene-3-(3′,5′-di-tert-butyl-4′-hydroxyphenyl)propionate]methane,2-tert-butyl-4-methyl-6-(2-acroyloxy-3-tert-butyl-5-methylbenzyl)phenol,3,9-bis[2-(3-tert-butyl-4-hydroxy-5-methylhydrocinnamoyloxy)-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane,and triethylene glycolbis[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate]. Of these,tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methaneis particularly preferably used, since the compound has excellent andlong-term antioxidation effect with respect to polyolefin.

As shown in electron microscope photographs of the below-describedExamples and the compositional analysis results, the polypropylene ofthe present invention attains a uniform composition throughout anindividual granule of the granular additive and exerts effect ofexcellently dispersing the granular additive in polyolefin. Thus, thepolypropylene of the present invention excellently promotes the effectsof the granular additive. No particular limitation is imposed on theform of the polypropylene, and powdery polypropylene is preferablyemployed, since the uniformity in composition throughout an individualgranule of the granular additive is enhanced. Examples of thepolypropylene include propylene homopolymer, random or block copolymersformed from C2-C10 α-olefin (other than propylene) and propylene(propylene content: 90 wt. % or more), and mixtures thereof. Melt indexthereof is not particularly limited.

In the multi-component granular additive for polyolefin of the presentinvention, when the above-mentioned polypropylene is added in an amountless than 5 parts by mass based on 10 parts by mass of the nucleatingagent, the aforementioned promotion effect cannot be attained, whereaswhen the amount of polypropylene is in excess of 50 parts by mass,enhancement of the effect commensurate with addition cannot be attainedand the amounts of other additive components relatively decrease,impairing advantages in weighing, transportation, etc. Therefore, theamount of polypropylene is 5-50 parts by mass, preferably 10-20 parts bymass.

The “at least one additive component” contained in the multi-componentadditive for polyolefin of the present invention refers to a variety ofinorganic and organic additives for use in polyolefin, other than theaforementioned nucleating agent and phenolic antioxidant. The species ofthe additive is not particularly limited, and the following additivesmay be employed.

Examples of phosphorus-containing antioxidants include triphenylphosphite, tris(2,4-di-tert-butylphenyl)phosphite,tris(2,5-di-tert-butylphenyl)phosphite, tris(nonylphenyl)phosphite,tris(dinonylphenyl) phosphite, tris(mono-, dinonylphenyl)phosphite,diphenyl acid phosphite, 2,2′-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite, diphenyl decyl phosphite, diphenyl octyl phosphite,di(nonylphenyl) pentaerythritol diphosphite, phenyl diisodecylphosphite, tributyl phosphite, tris(2-ethylhexyl)phosphite, tridecylphosphite, trilauryl phosphite, dibutyl acid phosphite, dilauryl acidphosphite, trilauryl trithiophosphite, bis(neopentyl glycol)1,4-cyclohexanedimethyl diphosphite,bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite,bis(2,5-di-tert-butylphenyl)pentaerythritol diphosphite,bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite,bis(2,4-dicumylphenyl) pentaerythritol diphosphite, distearylpentaerythritol diphosphite, tetra(C12-C15 mixedalkyl)-4,4′-isopropylidenediphenyl phosphite,bis[2,2′-methylenebis(4,6-diamylphenyl)]isopropylidenediphenylphosphite, tetratridecyl 4,4′-butylidenebis(2-tert-butyl-5-methylphenol)diphosphite, hexa(tridecyl)1,1,3-tris(2-methyl-5-tert-butyl-4-hydroxyphenyl)butane triphosphite,tetrakis(2,4-di-tert-butylphenyl)biphenylene diphosphonite,tris(2-[(2,4,7,9-tetrakis-tert-butyldibenzo[d,f][1,3,2]dioxaphosphepin-6-yl)oxy]ethyl)amine,9,10-dihydro-9-oxa-10-phosphaphenanthren-10-oxide, and2-butyl-2-ethylpropanediol 2,4,6-tri-tert-butylphenol monophosphite.

Examples of sulfur-containing antioxidants include dialkylthiodipropionates such as dilauryl thiodipropionate, dimyristylthiodipropionate, myristyl stearyl thiodipropionate, and distearylthiodipropionate; and polyol β-alkylmercaptopropionic acid esters suchas pentaerythritol tetra(β-dodecylmercaptopropionate).

Examples of hindered amine photostabilizers include compoundsrepresented by the following formula (II); cyanuric-chloride-condensatedproducts thereof; and high-molecular-weight species thereof:

wherein n represents an integer of 1 to 6; A represents a hydrogen atomor a C1-C18 n-valent hydrocarbon group, n-valent acyl group, or n-valentcarbamoyl group; B represents an oxygen atom, —NH—, or —NR′— having aC1-C8 alkyl group (R′); X represents a hydrogen atom, oxy radical (.O),a C1-C18 alkoxy group, a C1-C8 alkyl group, or a hydroxyl group; and Zrepresents a methine or a group having a C1-C8 alkyl group (R¹) andrepresented by the following formula (III).

Examples of the C1-C18 n-valent hydrocarbon group represented by A inthe above formula (II) include groups (alkyl to alkane(diyl to hexyl)groups) derived from methane, ethane, propane, butane, sec-butane,tert-butane, isobutane, pentane, isopentane, tert-pentane, hexane,cyclohexane, heptane, isoheptane, tert-heptane, n-octane, isooctane,tert-octane, 2-ethylhexane, nonane, isononane, decane, dodecane,tridecane, tetradecane, pentadecane, hexadecane, heptadecane, andoctadecane.

The “n-valent acryl group” refers to a group derived from a carboxylicacid, an n-valent carboxylic acid, or a polyvalent carboxylic acid alkylester having n residual carboxylic groups. Examples of acyl derivativecompounds include acetic acid, benzoic acid, 4-trifluoromethylbenzoicacid, salicylic acid, acrylic acid, methacrylic acid, oxalic acid,malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid,subelic acid, azelaic acid, sebacic acid, dodecanedioic acid,2-methylsuccinic acid, 2-methyladipic acid, 3-methyladipic acid,3-methylpentanedioic acid, 2-methyloctanedioic acid,3,8-dimethyldecanedioic acid, 3,7-dimethyldecanedioic acid, hydrogenateddimer acid, dimer acid, phthalic acid, terephthalic acid, isophthalicacid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid,trimellitic acid, trimesic acid, propane-1,2,3-tricarboxylic acid, (monoor di)-alkyl propane-1,2,3-tricarboxylate, pentane-1,3,5-tricarboxylicacid, (mono or di)-alkyl pentane-1,3,5-tricarboxylate,butane-1,2,3,4-tetracarboxylic acid, (mono to tri)-alkylbutane-1,2,3,4-tetracarboxylate, pentane-1,2,3,4,5-pentacarboxylic acid,(mono to tetra)-alkyl pentane-1,2,3,4,5-pentacarboxylate,hexane-1,2,3,4,5,6-hexacarboxylic acid, and (mono to penta)-alkylhexane-1,2,3,4,5,6-hexacarboxylate. The “n-valent carbamoyl group”refers to a monoalkylcarbamoyl group or a dialkylcarbamoyl group derivedfrom an isocyanate compound. Examples of isocyanate compounds whichderive a monoalkylcarbamoyl group include tolylene diisocyanate,diphenylmethane-4,4′-diisocyanate, p-phenylene diisocyanate, xylylenediisocyanate, 1,5-naphthylene diisocyanate,3,3′-dimethyldiphenyl-4,4′-diisocyanate, dianisidine diisocyanate,tetramethylxylylene diisocyanate, isophorone diisocyanate,dicyclohexylmethane-4,4′-diisocyanate, trans-1,4-cyclohexyldiisocyanate, norbornene diisocyanate, 1,6-hexamethylene diisocyanate,2,2,4(2,2,4)-trimethylhexamethylene diisocyanate, lysine diisocyanate,triphenylmethane triisocyanate, 1-methylbenzole-2,4,6-triisocyanate, anddimethyltriphenylmethane tetraisocyanate. Examples of dialkylcarbamyolgroups include diethylcarbamoyl, dibutylcarbamoyl, dihexylcarbamoyl, anddioctylcarbamoyl. These groups represented by A may be substituted by ahalogen atom, a hydroxyl group, an alkyl group, an alkoxy group, a nitrogroup, a cyano group, etc.

Examples of the C1-C8 alkyl group (R′) serving as B include methyl,ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, isobutyl, amyl,isoamyl, tert-amyl, hexyl, cyclohexyl, heptyl, isoheptyl, tert-heptyl,1-ethylpentyl, n-octyl, isooctyl, tert-octyl, and 2-ethylhexyl. Examplesof the C1-C18 alkoxy group represented by X include methoxy, ethoxy,propoxy, isopropoxy, butoxy, sec-butyloxy, tert-butyloxy, isobutyloxy,amyloxy, isoamyloxy, hexyloxy, heptyloxy, octyloxy, 2-ethylhexyloxy,nonyloxy, isononyloxy, decyloxy, dodecyloxy, tridecyloxy, tetradecyloxy,pentadecyloxy, hexadecyloxy, heptadecyloxy, and octadecyloxy. Examplesof the C1-C8 alkyl group are the same as those exemplified for R′ andexamples of the C1-C8 alkyl group (R¹) in Z are also the same as thoseexemplified for R′.

Specific examples of the hindered amine photostabilizer represented bythe above formula (II) include 2,2,6,6-tetramethyl-4-piperidyl stearate,1,2,2,6,6-pentamethyl-4-piperidyl stearate,2,2,6,6-tetramethyl-4-piperidyl benzoate,bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate,bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate,bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate,1,2,2,6,6-pentamethyl-4-piperidyl methacrylate,2,2,6,6-tetramethyl-piperidyl methacrylate,tetrakis(2,2,6,6-tetramethyl-4-piperidyl)1,2,3,4-butanetetracarboxylate,tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)1,2,3,4-butanetetracarboxylate,bis(2,2,6,6-tetramethyl-4-piperidyl)bis(tridecyl)1,2,3,4-butanetetracarboxylate,bis(1,2,2,6,6-pentamethyl-4-piperidyl)bis(tridecyl)1,2,3,4-butanetetracarboxylate,bis(1,2,2,6,6-pentamethyl-4-piperidyl)-2-butyl-2-(3,5-di-tert-butyl-4-hydroxybenzyl)malonate,3,9-bis[1,1-dimethyl-2-{tris(2,2,6,6-tetramethyl-4-piperidyloxycarbonyloxy)butylcarbonyloxy}ethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane,and3,9-bis[1,1-dimethyl-2-{tris(1,2,2,6,6-pentamethyl-4-piperidyloxycarbonyloxy)butylcarbonyloxy}ethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane.

Examples of the cyanuric-chloride-condensated products of the hinderedamine include1,6-bis(2,2,6,6-tetramethyl-4-piperidylamino)hexane/2,4-dichloro-6-morpholino-s-triazinepolycondensate,1,6-bis(2,2,6,6-tetramethyl-4-piperidylamino)hexane/2,4-dichloro-6-tert-octylamino-s-triazinepolycondensate,1,5,8,12-tetrakis[2,4-bis(N-butyl-N-(2,2,6,6-tetramethyl-4-piperidyl)amino)-s-triazin-6-yl]-1,5,8,12-tetrazadodecane,1,5,8,12-tetrakis[2,4-bis(N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidyl)amino)-s-triazin-6-yl]-1,5,8,12-tetrazadodecane,1,6,11-tris[2,4-bis(N-butyl-N-(2,2,6,6-tetramethyl-4-piperidyl)amino)-s-triazin-6-ylamino]undecane,and1,6,11-tris[2,4-bis(N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidyl)amino)-s-triazin-6-ylamino]undecane.

Examples of the high-molecular-weight species of the hindered amineinclude 1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-piperidinol/diethylsuccinate polycondensate and1,6-bis(2,2,6,6-tetramethyl-4-piperidylamino)hexane/dibromoethanepolycondensate.

Examples of UV-absorber-type photostabilizers include2-hydroxybenzophenones such as 2,4-dihydroxybenzophenone,2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, and5,5′-methylenebis(2-hydroxy-4-methoxybenzophenone);2-(2-hydroxyphenyl)benzotriazoles such as2-(2-hydroxy-5-methylphenyl)benzotriazole,2-(2-hydroxy-5-tert-octylphenyl)benzotriazole,2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole,2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole,2-(2-hydroxy-3,5-dicumylphenyl)benzotriazole,2,2′-methylenebis(4-tert-octyl-6-benzotriazolylphenol),2-(2-hydroxy-3-tert-butyl-5-carboxyphenyl)benzotriazole polyethyleneglycol ester,2-[2-hydroxy-3-(2-acryloyloxyethyl)-5-methylphenyl]benzotriazole,2-[2-hydroxy-3-(2-methacryloyloxyethyl)-5-tert-butylphenyl]benzotriazole,2-[2-hydroxy-3-(2-methacryloyloxyethyl)-5-tert-octylphenyl]benzotriazole,2-[2-hydroxy-3-(2-methacryloyloxyethyl)-5-tert-butylphenyl]-5-chlorobenzotriazole,2-[2-hydroxy-5-(2-methacryloyloxyethyl)phenyl]benzotriazole,2-[2-hydroxy-3-tert-butyl-5-(2-methacryloyloxyethyl)phenyl]benzotriazole,2-[2-hydroxy-3-tert-amyl-5-(2-methacryloyloxyethyl)phenyl]benzotriazole,2-[2-hydroxy-3-tert-butyl-5-(3-methacryloyloxypropyl)phenyl]-5-chlorobenzotriazole,2-[2-hydroxy-4-(2-methacryloyloxymethyl)phenyl]benzotriazole,2-[2-hydroxy-4-(3-methacryloyloxy-2-hydroxypropyl)phenyl]benzotriazole,and 2-[2-hydroxy-4-(3-methacryloyloxypropyl)phenyl]benzotriazole;2-(2-hydroxyphenyl)-4,6-diaryl-1,3,5-triazines such as2-[2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-1,3,5-triazine,2-[2-hydroxy-4-hexyloxyphenyl)-4,6-diphenyl-1,3,5-triazine,2-[2-hydroxy-4-octoxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-[2-hydroxy-4-(3-(C12-C13-mixed)-alkoxy-2-hydroxypropoxy)phenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-acryloyloxyethoxy)phenyl-4,6-bis(4-methylphenyl)-1,3,5-triazine,2-(2,4-dihydroxy-3-allylphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,and 2,4,6-tris(2-hydroxy-3-methyl-4-hexyloxyphenyl)-1,3,5-triazine;benzoates such as phenyl salicylate, resorcinol monobenzoate,2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate,hexadecyl-3,5-di-tert-butyl-4-hydroxybenzoate, andstearyl(3,5-di-tert-butyl-4-hydroxy)benzoate; substituted oxanilidessuch as 2-ethyl-2′-ethoxyoxanilide and 2-ethoxy-4′-dodecyloxanilide;cyanoacrylates such as ethyl-α-cyano-β,β-diphenyl acrylate andmethyl-2-cyano-3-methyl-3-(p-methoxyphenyl)acrylate; and metal salts andmetal chelates, inter alia nickel or chromium salts and chelates.

The alkali metal or alkaline earth metal salt of an aliphaticmonocarboxylic acid is added to polyolefin resin and serves as acatalyst deactivator or a nucleating aid. Examples of the aliphaticmonocarboxylic acid which provides the above salts include acetic acid,propionic acid, valeric acid, butyric acid, octylic acid, decanoic acid,lauric acid, myristic acid, palmitic acid, and stearic acid. Examples ofthe alkali metal which provides the above salts include lithium, sodium,and potassium. Examples of the alkaline earth metal which provides theabove salts include magnesium, calcium, strontium, and barium.

Examples of additives other than those described above include anantistatic agent comprising a nonionic surfactant, a cationicsurfactant, an anionic surfactant, an ampholytic surfactant, or asimilar substance; a flame retardant such as a halogen-containing agent,a phosphorus-containing agent, or a metal oxide; a lubricant such asethylenebis(alkylamide); a process aid; a filler; a colorant such as adye or a pigment; dibenzylidene sorbitol; an organic carboxylic acid;hydrotalcite; talc; and silica.

Of these, a phosphorus-containing antioxidant is particularly preferred,since the antioxidant exerts a synergistic effect when used incombination with a phenolic antioxidant. The alkali metal or alkalineearth metal salt of an aliphatic monocarboxylic acid is preferably used,since the salt improves thermal stability of polyolefin and exerts asynergistic effect when used in combination with a nucleating agent.

The amounts of the additive components to be incorporated into themulti-component granular additive for polyolefin of the presentinvention are the same as the amounts of the additive components whichwould have been required if directly added to polyolefin, and such thatexcellent mechanical strength and performance are imparted to themulti-component granular additive for polyolefin.

The amount of the additive of the present invention to be added topolyolefin preferably falls within a range where effect of the additivebegins to be manifested until the effect is no longer enhancedcommensurate with further addition. Based on 100 parts by mass ofpolyolefin, the amount of the nucleating agent is 0.01-3 parts by mass,the amount of the phenolic antioxidant is 0.01-5 parts by mass, and therespective amounts of the additives other than the nucleating agent andthe phenolic oxidant, the additives used in accordance with needs, are0.001-15 parts by mass. Among the additives used in accordance withneeds, the phosphorus-containing antioxidant, and the alkali metal oralkaline earth metal salt of an aliphatic monocarboxylic acid, which areincluded in examples of preferably employed additives, are each used inan amount of 0.001-5 parts by mass. Through the above formulation, acomposition containing polyolefin resin and the multi-component granularadditive for polyolefin of the present invention is provided.

The compositional proportions of the multi-component granular additivefor polyolefin of the present invention are determined such that themulti-component granular additive exhibits sufficient mechanicalstrength and the additive exerts favorable effect in the above-describedpolyolefin. Specifically, based on 10 parts by mass of the nucleatingagent, the phenolic antioxidant is used in an amount of 1-50 parts bymass, preferably 2-20 parts by mass. The additives other than thenucleating agent and the phenolic oxidant, the additives being used inaccordance with needs, generally do not comprise 10 or more components.When the total amount of the additives increases, mechanical strength ofgranules decreases. Accordingly, the total amount of the additives is0-500 parts by mass based on 10 parts by mass of the nucleating agent,preferably 100 parts by mass or less. Similar to the above case, thephosphorus-containing antioxidant and/or the alkali metal or alkalineearth metal salt of an aliphatic monocarboxylic acid are preferablyused. When these additives are used, the total amount of the additivesis preferably 1.0-100 parts by mass.

As described above, the nucleating agent is incorporated in themulti-component granular additive for polyolefin of the presentinvention in an amount of 1.64-62.5 mass %, preferably 3-60 mass %, morepreferably 10-50 mass %, from the viewpoint of well-balanced strengthand function of the produced granules.

No particular limitation is imposed on the form of particles of themulti-component granular additive for polyolefin of the presentinvention, and example forms include columnar, conical, prismatic,pyramidal, spherical, hemispherical, spheroidal, rugby-ball-like,egg-like, and cocoon-like. The mean particle size (sphere-equivalent) ispreferably 1.2-10 mm, more preferably 1.5-5 mm.

The “percent pulverization” of the multi-component granular additive forpolyolefin of the present invention as measured in a pulverizationacceleration test is represented by a ratio by mass of the particleswhich pass through a 16-mesh sieve during shaking by means of a shakingapparatus to the entire particles. Since the particles which passthrough a 16-mesh sieve mesh form airborne dust, which deterioratesoperational safety, the percent pulverization is preferably 1.0% orless.

The method of the present invention for producing the aforementionedmulti-component granular additive for polyolefin comprises mixing theabove-described nucleating agent, phenolic antioxidant, polypropylene,and, in accordance with needs, optional additive components other thanthe nucleating agent and the phenolic oxidant; and granulating theresultant mixture at 150° C. to 270° C. When the granulation temperatureis lower than 150° C., the produced granules have poor mechanicalstrength, thereby lowering the percent pulverization, whereas when thegranulation temperature is higher than 270° C., fluidity increases,thereby rendering granulation difficult. No particular limitation isimposed on the molding method and apparatus for performing granulationand other factors, and any customary molding method and apparatus can beemployed. Generally, a disk-pelleter method and an extrusion method areemployed as a granular production method. Of these, the extrusion methodis particularly preferred, since remarkably excellent strength isimparted to the produced granular additive.

No particular limitation is imposed on the type of polyolefin to whichthe multi-component granular additive of the present invention is added.Examples of the polyolefin include a-olefin polymers such as low-densitypolyethylene, linear-low-density polyethylene, high-densitypolyethylene, polypropylene, poly-1-butene, poly-3-methyl-1-butene, andpropylene/ethylene block or random copolymers. Of these, polypropyleneand ethylene/propylene block or random copolymers are particularlypreferred, since excellently promoted effects of addition are ensured.

No particular limitation is imposed on the end uses of theabove-described polyolefin, and examples include resin-made automobileparts such as bumpers, dashboards, and interior panels; resin parts ofhousehold electrical appliances such as refrigerators, washers, andvacuum cleaners; housewares such as tableware, buckets, and batharticles; general articles such as toys; and reservoirs and storagecontainers such as tanks. In addition to these molded products, exampleend uses include film products and fiber products of the polyolefin.

EXAMPLES

The present invention will next be described in more detail by way ofProduction Examples, Comparative Production Examples, EvaluationExamples, Examples, and Comparative Examples, which should not beconstrued as limiting the invention thereto.

Test Samples and Comparative Samples were prepared by use of aknead-extruder (model PCM 46, product of Ikegai) employing a die set(hole size: 2.5 mm, 16 holes), and a hot cut method. The producedpellets (multi-component granular additive) have a diameter of 2.5 mmand a length of 5-7 mm.

Production Example 1

Production of Test Sample A-1

Sodium 2,2′-methylenebis(4,6-di-tert-butylphenyl)phosphate (compound offormula 1; M=Na, n=1) serving as a nucleating agent (30 parts by mass);tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methaneserving as a phenolic antioxidant (10 parts by mass); polypropylenepowder (30 parts by mass); tris(2,4-di-tert-butylphenyl) phosphiteserving as a phosphorus-containing antioxidant (10 parts by mass); andcalcium stearate (alkali metal or alkaline earth metal salt of analiphatic monocarboxylic acid) (10 parts by mass) were mixed, and theresultant mixture was extruded under predetermined conditions (cylindertemperatures: 80° C. (entry), 140° C. (middle), 165° C. (exit), screwrotation for extrusion: 60 rpm, and amount of extrusion: 17.0 kg/Hr), tothereby produce pellets.

Production Example 2

Production of Test Sample A-2

The procedure of Production Example 1 was repeated, except thatextrusion conditions (cylinder temperatures: 80° C. (entry), 200° C.(middle), 165° C. (exit), screw rotation for extrusion: 60 rpm, andamount of extrusion: 17.4 kg/Hr) were employed instead of those ofProduction Example 1, to thereby produce pellets.

Production Example 3

Production of Test Sample A-3

The procedure of Production Example 1 was repeated, except thatextrusion conditions (cylinder temperatures: 80° C. (entry), 250° C.(middle), 200° C. (exit), screw rotation for extrusion: 60 rpm, andamount of extrusion: 19.0 kg/Hr) were employed instead of those ofProduction Example 1, to thereby produce pellets.

Production Example 4

Production of Test Sample B

Sodium benzoate serving as a nucleating agent (30 parts by mass);tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methaneserving as a phenolic antioxidant (10 parts by mass); polypropylenepowder (30 parts by mass); tris(2,4-di-tert-butylphenyl)phosphiteserving as a phosphorus-containing antioxidant (10 parts by mass); andcalcium stearate (alkali metal or alkaline earth metal salt of analiphatic monocarboxylic acid) (10 parts by mass) were mixed, and theresultant mixture was extruded under predetermined conditions (cylindertemperatures: 80° C. (entry), 140° C. (middle), 165° C. (exit), screwrotation for extrusion: 60 rpm, and amount of extrusion: 17.0 kg/Hr), tothereby produce pellets.

Production Example 5

Production of Test Sample C

Hydroxyaluminum 2,2′-methylenebis(4,6-di-tert-butylphenyl)phosphateserving as a nucleating agent (30 parts by mass);tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methaneserving as a phenolic antioxidant (10 parts by mass); polypropylenepowder (30 parts by mass); tris(2,4-di-tert-butylphenyl) phosphiteserving as a phosphorus-containing antioxidant (10 parts by mass);glycerin monostearate serving as an antistatic agent (5 parts by mass);lithium myristate (alkali metal or alkaline earth metal salt of analiphatic monocarboxylic acid) (15 parts by mass); and hydrotalciteDHT-4A (product of Kyowa Chemical Industry Co., Ltd.) (10 parts by mass)were mixed, and the resultant mixture was extruded under predeterminedconditions (cylinder temperatures: 80° C. (entry), 140° C. (middle),165° C. (exit), screw rotation for extrusion: 50 rpm, and amount ofextrusion: 17.0 kg/Hr), to thereby produce pellets.

Production Example 6

Production of Test Sample D

Sodium 2,2′-methylenebis(4,6-di-tert-butylphenyl)phosphate serving as anucleating agent (30 parts by mass);tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methaneserving as a phenolic antioxidant (10 parts by mass); and polypropylenepowder (30 parts by mass) were mixed, and the resultant mixture wasextruded under predetermined conditions (cylinder temperatures: 80° C.(entry), 140° C. (middle), 165° C. (exit), screw rotation for extrusion:60 rpm, and amount of extrusion: 17.0 kg/Hr), to thereby producepellets.

Production Example 7

Production of Test Sample E

Sodium 2,2′-methylenebis(4,6-di-tert-butylphenyl)phosphate serving as anucleating agent (20 parts by mass);tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methaneserving as a phenolic antioxidant (20 parts by mass); polypropylenepowder (20 parts by mass); tris(2,4-di-tert-butylphenyl)phosphiteserving as a phosphorus-containing antioxidant (10 parts by mass); andcalcium stearate (alkali metal or alkaline earth metal salt of analiphatic monocarboxylic acid) (10 parts by mass) were mixed, and theresultant mixture was extruded under predetermined conditions (cylindertemperatures: 80° C. (entry), 140° C. (middle), 165° C. (exit), screwrotation for extrusion: 60 rpm, and amount of extrusion: 17.0 kg/Hr), tothereby produce pellets.

Comparative Production Example 1

Production of Comparative Samples a, b, and c

The procedures of the aforementioned Production Examples 1, 4, and 5were repeated, except that no polypropylene powder was incorporated intoeach formulation, to thereby produce Comparative Samples a, b, and c,respectively.

Comparative Production Example 2

Production of Comparative Sample 1

Tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methaneserving as a phenolic antioxidant (10 parts by mass); polypropylenepowder (30 parts by mass); tris(2,4-di-tert-butylphenyl)phosphiteserving as a phosphorus-containing antioxidant (10 parts by mass); andcalcium stearate (alkali metal or alkaline earth metal salt of analiphatic monocarboxylic acid) (10 parts by mass) were mixed, and theresultant mixture was extruded under predetermined conditions (cylindertemperatures: 80° C. (entry), 140° C. (middle), 165° C. (exit), screwrotation for extrusion: 60 rpm, and amount of extrusion: 17.1 kg/Hr), tothereby produce pellets.

Evaluation Example 1

A broken surface of each of the thus-prepared Test Samples A-1 and B andComparative Samples a and b was observed under an electron microscopeand uniformity in composition was evaluated through EDS (energydispersive spectroscopy) analysis and EELS (electron energy lossspectroscopy) analysis. Each of FIGS. 1 to 4 shows an electronmicroscope photograph of a broken surface of a test sample and sites atwhich compositional analysis has been performed. The results are shownin Table 1.

TABLE 1 Detected Elements (count) Test Sample A-1 Point (1) Na(4,245),P(4,859), Ca(856) ″ Point (2) Na(4,377), P(5,130), Ca(922) Test Sample BPoint (3) Na(12,944), P(4,475), Ca(836) ″ Point (4) Na(13,123),P(4,622), Ca(854) Comp. Sample a Point (5) Na(4,061), P(4,687), Ca(945)″ Point (6) Na(1,785), P(5,397), Ca(240) Comp. Sample b Point (7)Na(15,435), P(4,745), Ca(811) ″ Point (8) Na(1,045), P(5,290), Ca(216)

Table 1 confirms that incorporation of polypropylene into themulti-component granular additive for polyolefin of the presentinvention provides compositional uniformity in granules of the additive.

Evaluation Example 2

Evaluation of Strength (Percent Pulverization, Hardness)

Some representative Test Samples and Comparative Samples which have beenproduced in the above Production Examples were evaluated in terms ofpercent pulverization and strength (Kiya-type hardness-meter). Thepercent pulverization was measured in the following manner.Specifically, each sample (100 g) which had not passed through a 16-meshsieve was placed in a plastic container (500 ml), and the sample wasshaken for four hours at 300 cycles/minute (amplitude: 40 mm). The ratioby mass of particles which had passed through the 16-mesh sieve to theentire particles was obtained. The results are shown in Table 2.

TABLE 2 Percent Test Sample Pulverization (%) Hardness (N) Test SampleA-1 0.20 25.5 Test Sample A-2 0.22 25.2 Test Sample A-3 0.20 25.3 TestSample B 0.24 25.0 Test Sample C 0.31 24.3 Test Sample D 0.20 26.1 TestSample E 0.28 24.8 Comparative Sample a 3.52 10.0 Comparative Sample b4.01 9.81 Comparative Sample c 3.76 9.84

Table 2 confirms that the multi-component granular additive forpolyolefin of the present invention has excellent mechanical strengthand can serve as a dust-free additive.

Evaluation Example 3

Each of the compositions shown in Tables 3 to 5 was mixed for fiveminutes by means of a Henschel mixer, and the resultant mixture wasextruded at 250° C. and 25 rpm, to thereby prepare pellets. The pelletswere injection-molded at 250° C., and the thus-produced test piece(thickness: 1 mm) was evaluated in terms of haze (JIS K7105) andflexural elasticity (ASTM D-747-63). Comparative Examples 1 to 3 containadditive components, shown in Table 3, for polypropylene, but the entirecomposition (formulation and components) of each mixture issubstantially the same as that of the mixture of Example 1. ComparativeExample 4 has a composition similar to that of Example 1, except that nonucleating agent is included. The entire composition (formulation andcomponents) of each mixture of Comparative Examples 5 and 6 issubstantially the same as that of the mixture of Example 3. The entirecomposition (formulation and components) of each mixture of ComparativeExamples 7 and 8 is substantially the same as that of the mixture ofExample 4.

TABLE 3 Flexural Composition Haze elasticity No. (ratio by mass) (%)(MPa) Example 1 Polypropylene (100) 31.5 1,506 Test Sample A-1 (0.3)Example 2 Polypropylene (100) 31.3 1,504 Test Sample D (0.3) ComparativePolypropylene (100) 35.3 1,415 Example 1 Comparative Sample a (0.3)Comparative Polypropylene 33.2 1,464 Example 2 Comparative Sample 1Nucleating agent Comparative Polypropylene 31.8 1,497 Example 3Nucleating agent Phenolic antioxidant Phosphoric antioxidant Aliphaticmonocarboxylic acid alkali metal or alkaline earth metal saltComparative Polypropylene 66.1 1,092 Example 4 Comparative Sample 1

TABLE 4 Flexural Composition Haze elasticity No. (ratio by mass) (%)(MPa) Example 3 Polypropylene (100) 56.3 1,364 Test Sample B (0.9)Comparative Polypropylene (100) 60.0 1,319 Example 5 Comparative Sampleb (0.9) Comparative Polypropylene 56.4 1,362 Example 6 Crystalnucleating agent Phenolic antioxidant Phosphoric antioxidant Aliphaticmonocarboxylic acid alkali metal or alkaline earth metal salt

TABLE 5 Flexural Composition Haze elasticity No. (ratio by mass) (%) MPaExample 4 Polypropylene (100) 17.4 1,416 Test Sample C (0.5) ComparativePolypropylene (100) 19.0 1,383 Example 7 Comparative Sample c (0.5)Comparative Polypropylene 17.4 1,414 Example 8 Phenolic antioxidantPhosphoric antioxidant Aliphatic monocarboxylic acid alkali metal oralkaline earth metal salt

Tables 3 to 5 confirm that when the multi-component granular additive ofthe present invention is added to polyolefin, excellent effect ofaddition, comparable to the cases of addition of non-integrated additivecomponents, can be obtained. Furthermore, through integration ofadditive components in granular form, airborne dust can be suppressed,and cumbersome work for formulating and uniformly mixing the additivescan be mitigated.

Industrial Applicability

The present invention provides a multi-component granular additive forpolyolefin, the additive having a strength and a function suitable forserving as a dust-free, components-in-granule additive.

What is claimed is:
 1. A multi-component granule additive forpolyolefin, the additive comprising a nucleating agent that comprises analkali metal salt or hydroxyaluminum salt of an aromatic monocarboxylicacid or comprises an alkali metal salt or hydroxyaluminum salt of anacid aromatic phosphoric ester compound, in an amount of 10 parts bymass; a phenolic antioxidant in an amount of 1-50 parts by mass;polypropylene in an amount of 5-50 parts by mass; and at least oneadditive component, serving as an optional component, other than thenucleating agent, the phenolic antioxidant, and the polypropylenecomponent in an amount of 0-500 parts by mass, wherein the granuleadditive has a ratio by mass (percent pulverization) of the particleswhich pass through a 16-mesh sieve of 1.0% or less as measured in apulverization acceleration test by use of a shaking apparatus.
 2. Amulti-component granule additive for polyolefin according to claim 1,wherein the nucleating agent is a compound represented by formula (I):

wherein n represents 1 or 2; when n is 1, M represents an alkali metalatom; and when n is 2, M represents hydroxyaluminum.
 3. Amulti-component granule additive for polyolefin according to claim 1,wherein the phenolic antioxidant istetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methane.4. A multi-component granule additive for polyolefin according to claim1, wherein said at least one additive component contains aphosphorus-containing antioxidant.
 5. A multi-component granule additivefor polyolefin according to claim 1, wherein said at least one additivecomponent contains an alkali metal salt or alkaline earth metal salt ofan aliphatic monocarboxylic acid.
 6. A method for producing amulti-component granular additive for polyolefin as recited in any oneof claims 1 to 5, said method comprising granulating a raw materialcomprising constitutional components at 150° C. to 270° C.
 7. Acomposition comprising polyolefin resin and the multi-component granuleadditive for polyolefin as recited in any one of claims 1 to 5.